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[Xen-devel] Re: [patch] provide uniqe x2apicid for each vcpu in the cpui

To: "Kamble, Nitin A" <nitin.a.kamble@xxxxxxxxx>
Subject: [Xen-devel] Re: [patch] provide uniqe x2apicid for each vcpu in the cpuid leaf 0xb
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Thu, 07 May 2009 19:14:28 +0100
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Hm, ok, well I think it is a pretty inoffensive patch anyway. I can queue it
for post 3.4.

 - Keir


On 07/05/2009 17:48, "Kamble, Nitin A" <nitin.a.kamble@xxxxxxxxx> wrote:

> Keir,
>    It is be used to find out the extended cpu topology of specified in the
> leaf 0xb.
> 
> Thanks & Regards,
> Nitin
> Linux Open Source Technology Center, Intel Corporation
> ----------------------------------------------------------------------------
> The Mind is like a parachute; it works much better when it's open.
> 
>> -----Original Message-----
>> From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx]
>> Sent: Thursday, May 07, 2009 12:05 AM
>> To: Kamble, Nitin A
>> Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
>> Subject: Re: [patch] provide uniqe x2apicid for each vcpu in the cpuid leaf
>> 0xb
>> 
>> What's the point of emulating an x2apicid when we don't emulate an x2apic?
>> 
>> -- Keir
>> 
>> On 06/05/2009 23:11, "Nitin A Kamble" <nitin.a.kamble@xxxxxxxxx> wrote:
>> 
>>> Keir,
>>> 
>>> Just like the apicid, x2apicid is also unique to each cpu. x2apicid is
>>> coming from edx register of the cpuid leaf 0xb.
>>> 
>>> Please Apply/comment.
>>> 
>>> Signed-Off-By: Nitin A Kamble <nitin.a.kamble@xxxxxxxxx>
>>> 
>>> 
>>> diff -r 08618cd10522 xen/arch/x86/hvm/hvm.c
>>> --- a/xen/arch/x86/hvm/hvm.c Mon May 04 14:13:49 2009 -0700
>>> +++ b/xen/arch/x86/hvm/hvm.c Mon May 04 14:19:05 2009 -0700
>>> @@ -1687,6 +1687,10 @@
>>>          *ebx |= (v->vcpu_id * 2) << 24;
>>>          if ( vlapic_hw_disabled(vcpu_vlapic(v)) )
>>>              __clear_bit(X86_FEATURE_APIC & 31, edx);
>>> +    } else if ( input == 0x0000000b )
>>> +    {
>>> +        /* fix the x2apicid */
>>> + *edx = v->vcpu_id * 2;
>>>      }
>>>  }
>>> 
>>> 
>> 
> 



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